Dry concentrator



April 28, 1925.

w. H. POWELL DRY CONCENTRATOR Filed y 17, 1924 4 Sheets-Sheet "1.lllllllll ...l|||l|ll|||l|| llllll lllll l I l l l l I I l l| llllllllw. H. POWELL DRY CONCENTRATCR Filed May 17, 1924 4 Sheets-Sheet 2 April28, 1925.

1,535,630v w. H. POWELL 152w cbncnnwnuon Filed May 17, 1924 as j 5 /7April 28, 192s.

w. H. POWELL DRY CONCENTRATOR Filed May 17, 1924 4 sheets-fine 4-Patented Apr. 28, 1925.

PATENT OFFICE.

WILLIAM H; POWELL, or. ALBUQUERQUE. NEW MEXICO.

nnY ooncnurnaroni Application filed May 17,

To all whom it may (rouccrn Be it known that I, TILL'IAMIII. Pownrm, acitizen of the United States, residing at Albuquerque, in the county ofBernalillo and Stateoi. New Mexico,- have invented certain new anduseful Improvements in Dry Concentrators; and I do hereby declare thefollowing tobe a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

My invention relates to a dryconcent 'ator for the treatment orconcentration of pulverized ore by the utilization of air currents, Theapparatus is more especially designed for the concentration of ore wherewater is not available.

The difierence in specific gravity between the precious metals andaccompanymg gangue has been generally avalled of in all efforts toconcentrate ores, One of the prerequisites of successful concentrationis that the ores must first be crushed or pnlverlzed to a point wherethe particles of precious metal are freed from the associated gangue.This pulverization sometimes results in the presence of a substantialquantity of gold in the very finely divided form commonly known as flourgold.

The common-1v practiced wet processes oii concentration, that isto say,those in which the separation is accomplished inthepresence of water,have universally failed to effeet a saving of the liner or flour goldbecause of the fact that the particles thereof are so small that theircapillary attraction or the presence of grease causes them to float uponthe ater and be carried away with the tailings. In a less'degree' thisis also true of leaf or sheet gold. g

Definite areas in this country areknown to contain gold in payingquantitiesybut the absence oi suflicient water available forconcentration of the ore has resulted in these properties remainingundevelopech The present apparatus is designedto accomplish theconcentration of ores by the use of air instead ofwater, thus ei'lablingproperties in arid regions, to be brought into production.

hentwo particles of equal volume but of different specific gravitiesaresubjectedtothe samecurrent of air, the heavier will settle more quicklyand closer to the source of the air current than will the lighterparticle. This fact has been availed of as one their greater niomentun1924-. Serial No. 713,975.

of the principles of operation of my apparatus. It alsois well knownthat if two particles of different specific gravities have the samevelocity imparted to them, the heavier will have the greater momentum,since momentum is theproduct of mass times the square of the velocity.This latter fact has beent-aken advantage of in my apparatus bydisposing riflled vanes at a slight angle to the direction of the airblast so that the blast will" force the material which it carriesagainst the vanes, the precious metals having the same velocity butagreater weight thus being driven into the rifl'les because of A primaryfeature of the invention, generally stated, consists in providing theapparatus with a series of vanes arranged in opposed sets so as to forma passage between them for the blast of air, the vanes being inclined tothe vertical so as to counteract the tendency of the air blast to bedeflected downward as a result of the ore particles falling through it,and also to assist the blast to carry the load of the ganguebydefleoting the blast upward. v

A further principal. feature of the invention consists, generallystated, in providing the vanes with riflies which incline slightlybackward into the blast so that their upper ends are somewhat nearer thesource of the blast than are their lower ends, thereby allowing theparticles caughtin the riflles to be thrown back as the carriages uponwhich the vanes are mounted are jigged, and enabling the material tofall freely. l p A still further feature of the invention involves theen' ploymentof a casing provided with an openinglfor introducingpulverized ore and having anoutlet for the es vcape of gangue and air,in combination with a plurality of reciprocating carriages arranged oneabove another within the easing andin open communication vertically,each of the ca'rriages being provided on opposite sides with a plurali y01 vanes set obliquely to the direction of reciprocationqof the;carriages and arranged in spaced and staggered relation so vas to formtortuous passages through which the air must pass, means forreciprocating the carriages with respect to each other, and means forcausing a blast of air to flow through the passages between the vanes. ia a a Another feature of the invention consists in employing a casingprovided with an opening for introducing pulverized ore and having'anoutlet for the escape of gangue and air, in combination with areciprocating carriage provided on opposite sides with a plurality ofvanes disposed obliquely with respect; to the reciprocation of thecarriage, the vanes on one side of the carriage being in staggeredrelation to those on the other side and being spaced to form a passagebetween them, means being provided for causing a blast of air to flowthrough the passage between the mics, and a series of screens forseparating or dispersii'ig the ore being interposed between the airriageand the opening in the casing for the admission of pulverized ore. I

Other features of the invention, residing in particular combinations ofparts and advantageous structural forms, will hereinafter appear and beparticularly pointed out in the claims.

In the drawings illustrating a preferred form of the apparatus,

Figure 1 is a side elevation of a dry concentrator embodying theinvention.

Figure 2 is a plan view of the construction shown in Fig. 1.

Figure I) a vertical central section of the apparatus shown in Fig. 1,the reciprocating carriages and associated vanes being in eleation;

Figure t is a detail transverse section on the line 4:4-. Fig. 3,looking in the direction of the arrows.

Figure 5 is a detail vertical section on the line .3-5, Fig. 2.

Figure 6 is a detail view, partly in plan and partly in section,illustrating a preferred form of mechanism for reciprocating or jiggingthe carriages.

Figure 7 is a plan view on a somewhat .eularged scale of one of thereciprocating carriages with the vanes removed.

Figure 8 is a plan view of one of the carriages and its associatedvanes.

*Figu-re 9 is a detail elevational view of a portion of one of thecarriages and the vanes mounted upon one side thereof.

Figure it) is a detail sectional view on the line 10-40, Fig. 9.

In the drawings, 1 indicates the casing of the concentrator apparatuswhich may adtrates containing the values fall and from which they may beremoved through a cleanout opening The end of the casing which isadjacent the ore admission opening 2 is in open eomn'iunication with oneor more conduits or windways (i which preferably correspond in number tothe number of reciprocating carriages with which the apparatus isequipped and which also preferably con'n'nunicate with the casing atpoints sul.)stantially opposite the adjacent ends of the carriages. Theair blast or air current may be produced in any desired manner,preferably by means of a fan T located within a suitable housing 8 whichcommunicates at one end with the several wind-ways (5 and is open to theatmosphere at its other end. Means are preferably provided forregulating the amount of air passing from the fan housing 8 to therespective pipes or wind ways (3, said means being conveniently forn'iedas hinged plates 9 whose pivoted ends are disposed adjacent to theneighboring walls of the wind-ways 6. as more particularly shown inFig. 1. plates may be swung up or down and may be fixed in theiradjusted positions by bolts 10 carried thereby and projecting outwardlythrough arcuate slots ll in the sides of the fan housing. Plates or caps12. which are secured to the hinged deflectors 9 through the bolts 10,serve to cover the slots 1]. in the fan casing S and also act as clampswhich press tightly against the adjacent walls of the fan casing andetii'ectively hold the hinged members 9 in position when the bolts 10are tightened.

For the purpose of feeding pulverized ore the casing 1 may have mountedupon it a hopper 13 comn'uinicating with the ore admission opening 2 ofthe casing. The flow of ore from the hopper may be convenientlyregulated or checked by means of a pair of contacting relatively movableslotted plates or grids l4 and 15, respectively, the former beingmovable and the latter stationary. By sliding the plate H with respectto the fixed plate '15 the openings in the two plates may be brought tosuch a relation as to feed pulverized ore to the casing at any desiredrate or to check its [low entirely, as will be readily understood. Thisis not only a simple and convenientmeans for controlling the feed of thepulverized ore. but it also has the advantage of distributing the orewith substantial uniformity to the set of screens 16 by which thematerial to be concentrated further dispersed or disseminated. Thesescreens are arranged below the opening 2 of the casing so as to diffusethe falling ore as it enters the apparatus and meets the first blast ofair, thus enabling the air to operate effectively upon the pulverizedmaterial.

The casing 1 is preferably provided upon its opposite sides withlongitudinally e.\'-

These pivoted tending horizontally disposed bars or plates 17 whichproject beyond the end of the casing a sutiicient distance to afiordmountings .tor the rotatable cam carrying shafts 18 by which the severalreciprocating 'arriages are jigged. The side plates 17, together withthe walls of the casing 1, allord extended support for "the horizontallydisposed journals 19 upon which the carriage supporting rollers 20 arerevolublymounted. These rollers are arranged horizontally opposite eachother in pairs and their journals are preferably screwed into the sidesof the alsing 1 so that they may be hm'izontally adjustable in or outfor the purpose of keep ing the reciprocating carriages in properalinement and elin'iinating any undue side play thereof. Above each pairot rollers the casing is provided on the inside with oppositely disposedlongitudi1mll ext-ending platesor filler members 21 whose inner facesare arranged closely adjacent the forward ends of the vanes so as toprevent any ot' the pulverized material carried in the blast frompassingbehindthe vanes. The side rails 23 ot the reciprocating carriagesQl ex tend under the lower ends of the fillers :21 and the upper endsofsaid fillers associated with the two lower carriagesare preferablybeveled as at 25. By this means little or no obstruction is offered tothe values as they drop. i a it The reciprocating carriages which arearranged one above another within the casing and provided withoppositelydisposed sets of vanes 22, are open top and bottom so as to be invertical communication with each other. i The frame ofeach carriage mayadvantageously be of skeleton construction formed of parallel horizontalangle irons 23 connected by suitable transverse ln'acing strapsQti.Oblique bracing straps 2i and 28, respectively, which are connected tothe side rails 23 and transverse braces 26 of the carriages, may been'n'iloyed to form means for securely supporting th'e=" \-"anes intheir assembled positions. Round headed stove bolts may convenientlybeemployed for attaching the vanes to the oblique braces 27 and 28. Theforward ends of the car riages may also advantageously be constructedw1th kneelbraces 29 for stitiening the ends ot'the carriageswherepggin'g force is applied.

Irfiorder that the mechanism by which the carriages are pgged shall notinterfere with arranging the air tubes or wind-ways (3 in horizontalalinement with the upper portions of thevanes 22; the side rails 23 ofthe carriages are spaced upwardly a short distancetron'i the lower edgesof the vanes associated therewith. This desired result' may be simplyeliecte'd by tornnng herfs or slots 30 in the lower edges or the severalvant ,slor the purpose of receiving the transversely extending bracing.straps 26. The

upper ends of the vanes 22 may be maintained in proper relation by meansof straps 31 extending between said vanes and secured thereto. a

The vanes 22, although adapted to be made of metal, are preferably ofwoodand may advantageously be seven sixtecnthsol an inch thick. Parallelrillles 32 are formed on the opposed or inner faces of the se'\'* eralvanes, the said riiiles preferably being small, set closely together andhaving their bottoms somewhat rounded so as to prevent the particlesotthe values from catching in sharp angles.

The vanes 22 on each side oi. each carriage are spaced with respect toeach other longitudinally of the apparatus, those on one side of thecarriage being in staggered or overlapping relation to those on theopposite side. The vanes extend obliquely iir ward from the oppositesides of the carriage so as to form a tortuous passage between themthrough which the air passes. In addition to being angularly disposedhorizontally with respect to each other the vanes on the opposite sidesof each carriage are preferably inclined to the vertical so as todiverge up *ardly, the anes at one side ol the carriage being inclinedto one side of the vertical and those at the other side of the carriagebeing inclined to the opposite side of the vertical. This setting of thevanes 22 at a slight angle to the vertical is advantageous in that itcounteracts the tend en'cy of the material tailing through the airblast. to deflect the blast downwardly; it also assists the current ofair to carry the load of the gangue by deflecting the blast u 'iwardly.

The jriflies 32 are inclined back "ardly into the current of air so thattheir upper ends are nearer the source of the blast; or, in other words.the ritiles are cut in the vanes at an angle which slightly forward ofthe normal to a horizontal line lying in the plane of the vane. Thisenables the materials caught in the l'lljllES to be thrown back as thevanes are jigged by the reciprr. eating carriages, and allows thematerial to fall freely. i

The reciprocating carriages provided with the vanes 22 are jigged so asto move with respect to each other by means of cams 33 carried by therespective cam shafts 18 and set one hundred and twenty degrees apart.These shafts, which are driven in unison. may advantageously be revolvedby the following mechanism: [Each of the cam shafts may have secured toit one or more sprocket wheels 34- as may be required to coo ierate withsuitable chain belts 35 enabling one shaft" to be driven from the other.one of'the shafts 18 being extended sutliciently to receive a beltpulley 36 For driving one of said shafts 18. The respective cams 33preferably cooperate with cam rollers 37 journaled on the ends of thrustrods 38 which are secured at their opposite ends to the correspondingcarriages 2-1. Surrounding each of the carriage actuating rods 38 andsecured thereto by means of a set screw, is a collar 39 which impingesagainst a metallic wear plate l0 forming a facing for the checking block4:1 secured to and extending between the adjacent side bars of plates 17of the casing. Encircling each thrust rod and interposed between theC011'6S1')O11(ll11g collar 39 and carriage 24 is a pipe or tube forminga buffer serving to hold the collar 39 in place under the shock of therecoil of the spring a3 interposed between said collar and the bearingblock 44- upon which one end of said spring rests, thus relieving theroller 37 from undue shock when the spring expands.

[n the operation of the apparatus it will be perceived that a downwardflow of pulverized ore is subjected to successive blasts or currents ofair which blow out the gangue or lighter matter. The larger particles ofthe precious metal, which because of their malleability have not beenpulverized to as great fineness as the gangue, readily separatethemselves from the latter and fall through the air blasts into the binat the bottom of the casing. Such *alues as may be carried by the blastsalong with the gangue will be forced against the successive vanes andthus be separated out of the blast and work downward so as to bedeposited in the bin.

In the particular form of apparatus illustrated in the drawings thepulverized ore is operated upon by three similar sets of :arriages 24.-with their associated rifiied vanes 22. the lower carriages beingslightly advanced successively in the direction of the blast. The valuesheld in the rifiles of the vanes of the uppermost carriage are workeddownward as the carriages are jigged. As the values pass to the set ofvanes on the carriage next below, the process is repeated, the valuesare further cleaned of gangue and more of the latter is carried off bythe air. These operations are repeated through the vanes on thelowermost carriage, so that the concentrates containing the valuesfinally fall into the bin a at the bottom of the apparatus while thegangue is carried away by the air and passes out of the apparatusthrough the opening 3 in the casing.

The presence of fine or flour gold in the pulverized ore may be met inoperation either by classification or by the reduction of the entireaggregate to the point where the particles of the gangue are the same orapproximately the same value as the gold. Greasy or rusty gold may beeffectively treated by the apparatus, since water is not used in theprocess and particles of that character, or course, maintain theirrelative specific gravity with respect to the gangue particles.

In operating the apparatus the strength of the air blast should besuited to the rate of flow of the pulverized ore, the fineness to whichit has been ground, and the presence therein of values in a very linestate. (lenerally speaking, the finer the ore can he successfullypulverized the better the concentration that can be accomplished; but itis to be observed that there is a point of din'iinishing return beyondwhich it is unprofitable to go because the cost of more finelypulverizing ore will not be warranted by the additional return. Thedrier the ore the more etliciently the concentrator will perform itsfunctions, and it is highly desirable that the presence of anyconsiderable amount of moisture in the ]')ulverized ore be avoided. Inorder to obtain the best results it is preferable to treat eachindividual ore by itself and to the carriages at the rate found mostsuitable for the air blast applied to a given How of the pulverizedmaterial. It has been found that jigging the carriages 2st at rates'arying from ten to sixty strokes per minute, depending upon the rate offlow of the ore and its character, iroduces satisfactory results.

lVhile I have shown and described a particular embodiment of theinvention, it is to be understood that I do not intend to limit myselfto precise details of construction, but regard the scope of my inventionas being broadly defined by the following claims.

I claim 1- 1. A dry concentrator involving a casing provided with anopening for introducing pulverized ore and having an outlet for theescape of gangue and air, a reciprocating carriage within said casingprovided on opposite sides with a plurality of vanes disposed obliquelyto the direction of recipro cation of said carriage, the vanes on oneside of the carriage being in staggered relation to those on the otherside, and means for causing a current of air to pass through said casingbetween said vanes.

2. A dry concentrator involving a casing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a series of vanes within said casing spaced from each other anddisposed in over-lapping relation so as to form a passage between them,some of said vanes being inclined to one side of the vertical and somebeing inclined to the other side of the vertical. and means for causinga current of air to pass through the passage between said vanes.

S A dry concentrator involving a casing provided with an openingtouintroducing pulverized ore and having-an outlet for the escape organgue and air, a series of vanes within said casing, said vanes beingarranged in oppositely disposed sets forming a passage between them, thevanes of one set being angularly disposed both vertically andhorizontallywithrespect to the van-es of the other set, and means forcausing a current oi? air to pass through the passage between saidvanes. a a

-.l:. A dry concentrator involving a, casing provided with an openingfor introducing pulverized ore and having an outlet for the escape ofgangue and air, a series of vanes in said casing arranged in opposedsets spaced to provide a passage between them, the vanes of each setbeing substantially parallel and disposed in spaced relation and thevanes of one set being staggered with respectto the vanes of the otherset, the vanes 01: each set forming an oblique angle with the *anes ofthe other set and. the said sets of vanes being inclined to the verticalso as, to diverge upwardly, and means for causing a current of air topass along the passage between said set of vanes.

5. A dry concentrator involvinga casing provided with an opening forintroducing pulverized ore and having an outlet for the escape oiigangue and air, of a series of vanes arranged in opposed sets spaced toafford a passage between them, and means for causing a current of: airto pass through said passage, the vanes oi cachset being obliquelydisposed with respect to the vanes of the other set and the vanes of therespective sets beinginclined to the vertical so as to diverge upwardly,each of said vanes being provided with a plurality of riflies which areinclined backwardly into said current of air.

6. A dry concentrator involving a casing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gaugueand air, of a series of vanes arranged in opposed sets ail'ording apassage between them, and means for causing a current of air to passthrough said passage,

each of the 'vanes being provide-d with a plurality of parallel rifiles,the vanes oi? one set being obliquely disposed with respect to the vanesoi the other set and the vanes of both sets being inclined to thevertical so as to diverge upwardly, and the said riflies being inclinedbackwardly into said current ot' a ir so that their lower ends areinadvance of their upper ends.

7. A dry concentrator involving a casing provided with an opening forintroducing pulverized ore and having an outlet forthe escape of gangueand air, .a reciprocating carriage provided on opposite sides with aplurality of vanes disposed obliquely to the direction of reciprocationof said carriage,

thevanes on one side oi said carriage ex tending at an angle to those onthe other side, means interposed between said carriage and said oreadmission opening in the casing torspreading said pulverized ore, andmeans for causing a current of air to pass through said casing betweensaid vanes. i

81A .dry concentrator involving a casing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a plurality of reciprocating carriages each provided onopposite sides with a plurality of vanes dis-v posed obliquely to thedirection of recipro cation of the said carriages, the vanes on one sideof each cz'irriage being in staggered relation to the vanes on the otherside o'fithe same carriage, and means for causing air to pass throughsaid casing between the vanes of the several carriages.

9. A dry concentrator involving a casing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a plurality of reciprocating carriages each provided onopposite sides with a plurality of vanes disposed obliquely to thedirection of reciprocation ot said carriages, said vanes also be iuginclined to the vertical, means for reciprocating said carriages tocause them to move with respect to each other, and means tor causing airto pass through said casing between the vanes and said carriages.

10. A dry concentrator involving a casing provided "with an opening forintroducing pulverizedore and having an outlet for the escape .otair andgangue, a reciprocating carriage within said casingprovided on oppositesides with a plurality of vanes disposed obliquely to the direction ofreciprocation oi. said carriage, the vanes on one side of the carriagebeing in staggered relation. to those on the other side so as to form atortuous passage between them, and means for causing a current of air topass along said passage.

11. A dry concentrator involving a casing provided with anopening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a plurality of reciprocating carriages arranged one above theother within said casing, said carriages being open vertically so as tocommunicate wvith each other and each being provided, with a series ofvanes spaced from each other and disposedfin overlapping relation so asto form a passage between them, some of the vanes on each of saidcarriages being inclined to one side of the vertical and some beinginclined to the opposite side of the vertical, means for reciprocatingsaid carriages so as to cause them to move with relation to each other,and means for causing air to pass through said casing between saidvanes.

.12. A dry concentrator involving a casing provided with an'opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a plurality oi reciprocating carriages having closed sides andopen at top and bottom, each of said carriages being provided onopposite sides with a plurality of vanes disposed obliquely to thedirection or reciprocation ot the said carriages, the vanes on one sideof each carriage being inclined to one side of the vertical and those onthe other side ot the same carriage being inclined to the other side ofthe vertical, and means for causing a current of air to pass through thecasing between said vanes.

13. A dry concentrator involving a casing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a plurality of reciprocating carriages arranged one aboveanother within said casing and in open communication vertically, each ofsaid carriages being provided on opposite sides with a plurality ofvanes disposed obliquely to the direction of reciprocation of saidcarriages, the vanes on the opposite sides of each carriage t'orniing atortuous passage between them, means for reciprocating said carriages soas to cause them to move with respect to each other, and means forcausing air to pass through said passages between said vanes.

l-t. A dry concentratm' involving a casing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a reciprocating carriage provided on opposite sides with aplurality of vanes disposed obliquely with respect to the direction ofreciprocation of said carriage, the vanes on one side ot the carriagebeing in staggered relation to those on the other side and being spacedtherefrom so as to form a tortuous passage therebetween, a series ofscreens interposed between said carriage and the openin in said casingtor the admission of pulverized ore. valve means for controlling thedelivery ot pulverized ore to said screens, and means for causing acurrent of air to pass through the passage between said vanes.

15. A dry concentrator involving :1 casing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a plurality of reciprocating carriages arranged one aboveanother within said casing and in open communication vertically witheach other. a. series of anes mounted upon each of said carriages, saidvanes being provided with riflles and being arranged in oppositelydisposed sets forming a passage between them. the vanes of one set beingangularly disposed both vertically and horizontally with respect to the"anes ot the other set. means for reciprccating said carriages so as tomove them with respect to each other, and means for causing air to passthrough the passages between said vanes.

16. A dry concentrator involving a casing I provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a plurality of relatively movable reciprocating carriagesarranged one above another within said casing, each of said carriagesbeing provided with a plurality of oppositely disposed 'anes havingrifl'les, said vanes on each carriage being arranged in oppositelydisposed sets forming a nissage between them, the vanes on one side ofeach carriage being disposed at an angle to those on the other side ofthe same carriage, means tor reciprocating said carriages so as to causethem to move with relation to each other, and means for introducing aircurrents into said casing substantially opposite the corresponding endsof each of said carriages.

17. A dry concentrator involving a casing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air. a plurality of reciprocating carriages open at top and bottomand arranged one above another within said casing, each of saidcarriages being provided with opposed sets of ri'llled vanes spaced toprovide a passage between them, the *anes of each set being in spacedrelation and the allies of one set being staggered with respect to thevanes of the other set on the same carriage, the sets of vanes on eachcarriage being inclined to the vertical. so as to diverge up *ardly.n'ieans for reciprocating said carriages. and means for causingair topass through the passages between said vanes.

18 A dry concentrator involving a 'asing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a plurality o't' re ci1r rocating carriages arranged one aboveanother within said casing. said carriages being open at the top andbottom and each being provided with a plurality ot 'anes arranged inopposed sets affording a passage between them, means for reciprocatingsaid carriages so as to cause them to move with respect to each other.and means for causing air to pass through said passages between saidvanes, the vanes of each set on each carriage being obliquely disposedwith respect to the other set on the same carriage and the allies ofboth sets on each carriage being'inclined to the vertical so as todiverge upwardly, and each of the vanes being provided with a pluralityof ritlles which incline backwardly into said current of air so thattheir lower ends are in advance of their upper ends. I

19. A dry concentrator involving a casing provided with an opening forintroducing pulverized ore and having an outlet for the escape of gangueand air, a plurality of reciprocating carriages open at top and bottomand ar 'anged one above the other Within said casing, means interposedbetween the uppermost carriage and the ore admission opening in thecasing for spreading the pulvized ore, each of said carriages beingprovided with a series of vanes arranged in opposed sets forming apassage between them, means for synchronously reciprocating saidcarriages so as to cause them to move with respect to each other, andmeans for intr0- ducing'currents of air into said casing substantiallyopposite the corresponding ends of said carriages, the vanes of each setupon each carriage being obliquely disposed with respect to the vanes ofthe other set on the same carriage, the vanes of the respective sets oneach carriage being inclined to the vertical so as to diverge upwardly,and each of said vanes being provided with a plu' rality of riflieswhich incline backwardly toward the air currents so that their lowerends are in advance of their upper ends.

In testimony whereof I atliX my signa ture, in the presence of twosubscribing \vitnesses.

fitnesses E. L. FLANERY, M. Vixen.

WILLIAM H. POWELL.

